Is Iron and oxygen forming rust a chemical or physical change

Explanation:

When an iron object is left in damp air for a considerable time, it gets covered with a reddish- brown flaky substance called rust. This is called rusting of iron. The process of rusting is represented as follows: Rusting of iron is a chemical change because a new substance iron oxide is formed.

It is a chemical change.

Explanation:

• A chemical change is a change that cannot be reversed.

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm